Conventionally, there is a display media referred to as electronic paper. The electronic paper maintains visibility and portability which are regarded as the advantage of paper, and allows the displayed content to be electrically rewritten. The representative display technique of the electronic paper is the electrophoretic system. Electronic paper 101 of this system is developed by E Ink Corporation, US. In the electronic paper 101 of this scheme, each microcapsule 43 accommodates white particles, black particles, and fluid. The white particles and the black particles are shifted by an electric field, whereby a black-and-white display is presented (see Patent Document 1). More specifically, in each transparent microcapsule 43 having a diameter of about 40 μm, positively charged white pigment particles 44 and negatively charged black pigment particles 45 are accommodated with a transparent dispersion medium (oil) 46. The capsules are each structured with only a single thin layer, and are aligned between two narrow electrode plates without any space. One side of the electrode serving as the display surface (front surface layer) 41 is made of a transparent electrode 42 such as ITO, and an electrode 47 on the opposite side is supported by a support layer 48, and is structured with fine rectangular electrodes having the display resolution of a required degree (see FIG. 3). By application of voltage from an external control circuit, an electric field generates between the two electrodes 42 and 47, and the positively and negatively charged white and black pigment particles 44 and 45 migrate in the oil 46. Then, the pigment particles 44 or 45 of the color selected by the voltage gather on the display surface side of the capsule 43, to present black and white display. For each display is selected. For example, in FIG. 3, white color is displayed by external light 49 (see reference character 50), and black color is displayed by the external light 49 (see reference character 51). Since the pigment particles 44 and 45 do not easily move even when the voltage is turned off, it can be read as printed matter.
For its characteristics such as low power consumption and high visibility, products using the electronic paper, e.g., various mobile phones, electronic book readers, are now commercially available, and are so popular that they are introduced into digital signage. In addition, what is coming into use lately is application of a touch panel to the electronic paper.
Meanwhile, since the electronic paper 101 presents display using reflected light similarly to paper, electronic paper 101 has a wide viewing angle. Even when the electronic paper 101 is irradiated with direct sunlight, electronic paper 101 is easily recognizable and puts less burden on the eyes. However, as described above, when the resistive film type touch panel 102 is disposed on the front surface side of the electronic paper 101, light reflects off the front surface of the resistive film type touch panel 102, between the electrodes thereof, the back surface thereof, and the like (see FIG. 4). This invites a problem that the excellent visibility that is inherent to the electronic paper 101 is impaired, and burden on the eyes is great.
On the other hand, there is another technique in which a capacitive type touch panel is disposed on the back surface side of the electronic paper. In this case, since the electronic paper is positioned at the topmost surface, visibility will not be impaired. However, with the capacitive type touch panel, an input cannot be carried out with a pen.
Accordingly, currently, it is required to dispose the resistive film type touch panel 102 on the back surface side of the electronic paper 101 (see FIG. 5), such that an input is entered via the electronic paper 101.